This invention relates to a rotary fluid compressor for automotive vehicles.
Existing automotive vehicles, such as air braked trucks, use reciprocating piston air compressors to provide a source of compressed air. However, rotary air compressors offer significant advantages over the older reciprocating piston compressors. The present invention relates to a rotary compressor in which a two-lobed rotor rotates within an epitrochoidal housing to compress air. The air is then communicated to storage reservoirs for use in the vehicle air brake system and to operate vehicle accessory devices that depend upon air pressure. Many prior art rotary compressors are inefficient, noisy, and do not run smoothly, so they have generally not been used on automotive vehicles. The prior art compressors are relatively inefficient because they do not make efficient use of the displacement volume. They do not run smoothly, because they are designed such that a reversing torque is applied to the rotor during some portions of its angular movement, thereby introducing vibration. These prior art compressors are often noisy, because they discharge compressed air to atmosphere through the inlet port during some phases of their operation, thereby causing an unpleasant "popping" sound, and additional reductions in efficiency. When used on a vehicle, this "popping" sound is so loud that it may cause the compressor to violate the noise standards of governmental agencies.